See below for the page counts and number of frames. Please be careful about assuming less or more pages/frames means less or more play time. There are a lot of factors that go into that, some books may have more multi-frame entries, some may have gameplay that takes longer based on a variety of factors, etc - including your individual play experience based on the choices you make! In short, our recommendation is that you pick the books that interest you the most, regardless of page count.
Here are the specific page and frame counts by book:
Mystery: 152 Pages / 298 Frames
Sherlock and Moriarty: 152 Pages / 275 Frames
Sherlock and Irene: 104 Pages / 194 Frames
Pirates: The Great Chase: 152 Pages / 356 Frames
Pirates: The City of Skulls: 152 Pages / 359 Frames